Weekly Opportunity Picks #1: A 90,000-user Pomodoro timer left the Chrome store.
Weekly Opportunity Picks #1: A 90,000-user Pomodoro timer left the Chrome store. Alternatives caught only ~11%.
Five Chrome extension gaps from this week, two ideas we killed, and the public scorecards for our own three launches.
Building is cheap now; knowing what to build isn't. Every day I scan public Chrome Web Store data for extension opportunities, and an AI researches each one on the web to judge whether it's worth building. It can be wrong; when it is, tell me.
This is issue #1: five picks from the daily lists of September 28 to October 4, two rejects, and an update on our own three extensions.
Each pick names its signal, our reason a gap exists:
- Abandoned Users: a popular extension was removed, broke or was pulled, and its users haven't found a replacement.
- Leader Went Bad: a leading extension got worse (a paywall, a broken update, no maintenance) and its ratings are falling.
- Rising Demand: clearly more people use this than a year ago, and newcomers still win users.
1. Users of Marinara: Pomodoro® Assistant (Pomodoro timer)
What to build: A lightweight, no-account, keyboard-first Pomodoro timer for the people Marinara left behind.
Signal: Abandoned Users
Why now: Marinara had 90,000 users before its removal around August 31, 2026. By our estimate from alternatives' user growth, only about 11% have been picked up by alternatives, which mostly lean toward task management or site blocking. People who just want a clean timer are left out.
Biggest risk: The store gives no removal reason and we couldn't verify the real one, so a rebuild could run into the same problem.
2. An alternative to Multiselect for YouTube™
What to build: A bulk playlist manager for YouTube users drowning in Watch Later and liked videos: data stays on your device, bulk actions stay free, updates keep coming.
Signal: Leader Went Bad
Why now: Multiselect hasn't been updated since October 2024. Its rating fell from 4.08 to 2.55, and this year's 1-star reviews keep saying "no longer works." Meanwhile the need is up +59.6% year over year.
Biggest risk: PocketTube (updated July 2026) and Watch Later Tidy have already caught some of these users, so you'd win on "no locked features, no donation pop-ups."
3. An alternative to YouTube Tags
What to build: A free, no-login tool that shows a YouTube video's hidden tags right on the watch page and lets you copy them.
Signal: Leader Went Bad
Why now: YouTube Tags has 100,000 users. In August 2026 it added a Google sign-in, a $50–100 paywall and blurred tags. Over the last 90 days its rating went from 4.77 to 4.25. The alternatives all have 0–8K users, and some are unmaintained or trial-gated. Nobody has caught these users yet.
Biggest risk: Our data counts none of the 4 products here as paid yet (the leader's paywall is only weeks old), so nobody has shown it can make money.
4. An alternative to The Marvellous Suspender
What to build: A clean, open-source tab suspender: idle tabs sleep to save memory and wake up exactly as you left them.
Signal: Leader Went Bad
Why now: The Marvellous Suspender (100,000 users) broke during Chrome's forced move to a new extension format. Tabs woke up on their own, tab groups got lost and permissions grew. Reviews from the last 3 months average 2.8 stars, down from 3.36 over the 9 months before, and users are publicly asking for a replacement. The broader need has 649k users and grew +23.5% in 90 days. One alternative hasn't been updated in two years; another sits at 3.72.
Biggest risk: Chrome's built-in Memory Saver covers most casual users; the opening is heavy tab users, who are hard to charge.
5. Users of Pasar Lista en Meet (Google Meet attendance)
What to build: One-click attendance for teachers on free Google Meet accounts, Spanish and Portuguese first, exporting time, duration and attendance rate to a spreadsheet.
Signal: Abandoned Users
Why now: Pasar Lista en Meet had 50k users before it disappeared around August 31, 2026, and only 2% have been caught by alternatives. The research blames Chrome retiring its old extension format, which a rebuild should avoid. The need behind it has 695k users and grew +19.3% in 90 days, yet the leading product is rated only 2.8 out of 5. The alternatives are English-first, and the Spanish ones are outdated.
Biggest risk: We found no paying users in this category, so revenue is unknown.
Two we said no to
- Copy an element's HTML and CSS (Rising Demand). People really do want to feed page styles to AI coding agents. But "supply hasn't caught up" fell apart: about a dozen direct competitors, most listed in 2026, plus the browser's free developer tools and an MIT-licensed open-source option. It looked empty; it's crowded.
- Game redemption codes (Rising Demand). Real growth, but tied to one game and one publisher. The only validated way to win is auto-submitting codes, which breaks Garena's rules, counts as a store violation and gets users permanently banned. The rule-abiding version showed no demand or revenue evidence.
Our own three extensions
We launched three extensions on September 28–29, picked with this same process, each with public 4-week success criteria so we can't move the goalposts. "Organic" excludes installs from our own promotion.
- 01 Page to Markdown for AI – Token Counter (live Sep 29, Rising Demand): ≥500 organic installs; "copy as markdown" or "page to markdown" in the store's top 10 search results; rating ≥4.5 (≥5 ratings).
- 02 Reopen Closed Tabs – Tab History & Sessions (live Sep 28, Abandoned Users): ≥300 organic installs; "undo closed tab" or "restore closed tabs" in the top 10; rating ≥4.3; 4-week uninstall rate <40%. It also has a kill condition: fewer than 100 installs in 4 weeks means the Abandoned Users idea didn't hold up in this case.
- 03 Bookmark Rewind – Backup, Restore & Sync (live Sep 28, Leader Complaints: leaders' bad reviews cluster on a fixable problem): ≥300 organic installs; "bookmark backup" or "restore bookmarks" in the top 10; rating ≥4.3; 4-week uninstall rate <40%.
Day-7 numbers are waiting on a developer-console export. I'll check them against these targets next week, good or bad.
Your turn
Hit reply and tell me: what are you building, and which direction would you like us to look at? Good ones may end up in a future issue.
Full evidence and research reports for every pick are in the trial space. Sign up at numberandreason.com to get access.
Data: Chrome-Stats, processed by us, plus public Chrome Web Store pages.
— Reid